Adding "BigIntegerField" to work with "legacy" tables that use bigints as keys.
(The preferred fix would be for Django issue 399 to land, and let the field size of Auto fields be specified.)
This field is being added to address issue 54.

Created a branch for Django 1.0.
Django revision 10026 changed how database backends receive settings. This is a backwards-incompatible change. Our trunk will still track Django's trunk. The new "legacy-1.0"
branch will remain compatible with Django 1.0.x, though probably with unfixed bugs.

Fix for issue 48, changed
if self.high_mark and not self.low_mark:
to
if self.high_mark is not None and not self.low_mark:
if "self.high_mark" is 0, then we let the logic happen, which will generate "top 0" and return no rows.